//
// execution/submit.hpp
// ~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef ASIO_EXECUTION_SUBMIT_HPP
#define ASIO_EXECUTION_SUBMIT_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include "asio/detail/config.hpp"
#include "asio/detail/type_traits.hpp"
#include "asio/execution/detail/submit_receiver.hpp"
#include "asio/execution/executor.hpp"
#include "asio/execution/receiver.hpp"
#include "asio/execution/sender.hpp"
#include "asio/execution/start.hpp"
#include "asio/traits/submit_member.hpp"
#include "asio/traits/submit_free.hpp"

#include "asio/detail/push_options.hpp"

#if defined(GENERATING_DOCUMENTATION)

namespace asio {
namespace execution {

/// A customisation point that submits a sender to a receiver.
/**
 * The name <tt>execution::submit</tt> denotes a customisation point object. For
 * some subexpressions <tt>s</tt> and <tt>r</tt>, let <tt>S</tt> be a type such
 * that <tt>decltype((s))</tt> is <tt>S</tt> and let <tt>R</tt> be a type such
 * that <tt>decltype((r))</tt> is <tt>R</tt>. The expression
 * <tt>execution::submit(s, r)</tt> is ill-formed if <tt>sender_to<S, R></tt> is
 * not <tt>true</tt>. Otherwise, it is expression-equivalent to:
 *
 * @li <tt>s.submit(r)</tt>, if that expression is valid and <tt>S</tt> models
 *   <tt>sender</tt>. If the function selected does not submit the receiver
 *   object <tt>r</tt> via the sender <tt>s</tt>, the program is ill-formed with
 *   no diagnostic required.
 *
 * @li Otherwise, <tt>submit(s, r)</tt>, if that expression is valid and
 *   <tt>S</tt> models <tt>sender</tt>, with overload resolution performed in a
 *   context that includes the declaration <tt>void submit();</tt> and that does
 *   not include a declaration of <tt>execution::submit</tt>. If the function
 *   selected by overload resolution does not submit the receiver object
 *   <tt>r</tt> via the sender <tt>s</tt>, the program is ill-formed with no
 *   diagnostic required.
 *
 * @li Otherwise, <tt>execution::start((new submit_receiver<S,
 *   R>{s,r})->state_)</tt>, where <tt>submit_receiver</tt> is an
 *   implementation-defined class template equivalent to:
 *   @code template<class S, class R>
 *   struct submit_receiver {
 *     struct wrap {
 *       submit_receiver * p_;
 *       template<class...As>
 *         requires receiver_of<R, As...>
 *       void set_value(As&&... as) &&
 *         noexcept(is_nothrow_receiver_of_v<R, As...>) {
 *         execution::set_value(std::move(p_->r_), (As&&) as...);
 *         delete p_;
 *       }
 *       template<class E>
 *         requires receiver<R, E>
 *       void set_error(E&& e) && noexcept {
 *         execution::set_error(std::move(p_->r_), (E&&) e);
 *         delete p_;
 *       }
 *       void set_done() && noexcept {
 *         execution::set_done(std::move(p_->r_));
 *         delete p_;
 *       }
 *     };
 *     remove_cvref_t<R> r_;
 *     connect_result_t<S, wrap> state_;
 *     submit_receiver(S&& s, R&& r)
 *       : r_((R&&) r)
 *       , state_(execution::connect((S&&) s, wrap{this})) {}
 *   };
 *   @endcode
 */
inline constexpr unspecified submit = unspecified;

/// A type trait that determines whether a @c submit expression is
/// well-formed.
/**
 * Class template @c can_submit is a trait that is derived from
 * @c true_type if the expression <tt>execution::submit(std::declval<R>(),
 * std::declval<E>())</tt> is well formed; otherwise @c false_type.
 */
template <typename S, typename R>
struct can_submit :
  integral_constant<bool, automatically_determined>
{
};

} // namespace execution
} // namespace asio

#else // defined(GENERATING_DOCUMENTATION)

namespace asio_execution_submit_fn {

    using asio::declval;
    using asio::enable_if;
    using asio::execution::is_sender_to;
    using asio::traits::submit_free;
    using asio::traits::submit_member;

    void submit();

    enum overload_type {
        call_member,
        call_free,
        adapter,
        ill_formed
    };

    template<typename S, typename R, typename = void,
            typename = void, typename = void>
    struct call_traits {
        ASIO_STATIC_CONSTEXPR(overload_type, overload = ill_formed
        );

        ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false);

        typedef void result_type;
    };

    template<typename S, typename R>
    struct call_traits<S, void(R),
            typename enable_if<
                    submit_member<S, R>::is_valid
            >::type,
            typename enable_if<
                    is_sender_to<S, R>::value
            >::type> :
            submit_member<S, R> {
        ASIO_STATIC_CONSTEXPR(overload_type, overload = call_member);
    };

    template<typename S, typename R>
    struct call_traits<S, void(R),
            typename enable_if<
                    !submit_member<S, R>::is_valid
            >::type,
            typename enable_if<
                    submit_free<S, R>::is_valid
            >::type,
            typename enable_if<
                    is_sender_to<S, R>::value
            >::type> :
            submit_free<S, R> {
        ASIO_STATIC_CONSTEXPR(overload_type, overload = call_free);
    };

    template<typename S, typename R>
    struct call_traits<S, void(R),
            typename enable_if<
                    !submit_member<S, R>::is_valid
            >::type,
            typename enable_if<
                    !submit_free<S, R>::is_valid
            >::type,
            typename enable_if<
                    is_sender_to<S, R>::value
            >::type> {
        ASIO_STATIC_CONSTEXPR(overload_type, overload = adapter
        );

        ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false);

        typedef void result_type;
    };

    struct impl {
#if defined(ASIO_HAS_MOVE)
        template <typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
          call_traits<S, void(R)>::overload == call_member,
          typename call_traits<S, void(R)>::result_type
        >::type
        operator()(S&& s, R&& r) const
          ASIO_NOEXCEPT_IF((
            call_traits<S, void(R)>::is_noexcept))
        {
          return ASIO_MOVE_CAST(S)(s).submit(ASIO_MOVE_CAST(R)(r));
        }

        template <typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
          call_traits<S, void(R)>::overload == call_free,
          typename call_traits<S, void(R)>::result_type
        >::type
        operator()(S&& s, R&& r) const
          ASIO_NOEXCEPT_IF((
            call_traits<S, void(R)>::is_noexcept))
        {
          return submit(ASIO_MOVE_CAST(S)(s), ASIO_MOVE_CAST(R)(r));
        }

        template <typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
          call_traits<S, void(R)>::overload == adapter,
          typename call_traits<S, void(R)>::result_type
        >::type
        operator()(S&& s, R&& r) const
          ASIO_NOEXCEPT_IF((
            call_traits<S, void(R)>::is_noexcept))
        {
          return asio::execution::start(
              (new asio::execution::detail::submit_receiver<S, R>(
                ASIO_MOVE_CAST(S)(s), ASIO_MOVE_CAST(R)(r)))->state_);
        }
#else // defined(ASIO_HAS_MOVE)
        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<S &, void(R &)>::overload == call_member,
                typename call_traits<S &, void(R &)>::result_type
        >::type

        operator()(S &s, R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<S &, void(R & )>::is_noexcept))
                {
                        return s.submit(r);
                }

        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<const S &, void(R &)>::overload == call_member,
                typename call_traits<const S &, void(R & )>::result_type
        >::type

        operator()(const S &s, R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<const S &, void(R & )>::is_noexcept))
                {
                        return s.submit(r);
                }

        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<S &, void(R &)>::overload == call_free,
                typename call_traits<S &, void(R & )>::result_type
        >::type

        operator()(S &s, R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<S &, void(R & )>::is_noexcept))
                {
                        return submit(s, r);
                }

        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<const S &, void(R &)>::overload == call_free,
                typename call_traits<const S &, void(R & )>::result_type
        >::type

        operator()(const S &s, R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<const S &, void(R & )>::is_noexcept))
                {
                        return submit(s, r);
                }

        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<S &, void(R &)>::overload == adapter,
                typename call_traits<S &, void(R & )>::result_type
        >::type

        operator()(S &s, R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<S &, void(R & )>::is_noexcept))
                {
                        return asio::execution::start(
                        (new asio::execution::detail::submit_receiver<
                        S&, R&>(s, r))->state_);
                }

        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<const S &, void(R &)>::overload == adapter,
                typename call_traits<const S &, void(R & )>::result_type
        >::type

        operator()(const S &s, R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<const S &, void(R & )>::is_noexcept))
                {
                        asio::execution::start(
                                (new asio::execution::detail::submit_receiver<
                                        const S &, R &>(s, r))->state_);
                }

        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<S &, void(const R &)>::overload == call_member,
                typename call_traits<S &, void(const R &)>::result_type
        >::type

        operator()(S &s, const R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<S &, void(const R &)>::is_noexcept))
                {
                        return s.submit(r);
                }

        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<const S &, void(const R &)>::overload == call_member,
                typename call_traits<const S &, void(const R &)>::result_type
        >::type

        operator()(const S &s, const R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<const S &, void(const R &)>::is_noexcept))
                {
                        return s.submit(r);
                }

        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<S &, void(const R &)>::overload == call_free,
                typename call_traits<S &, void(const R &)>::result_type
        >::type

        operator()(S &s, const R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<S &, void(const R &)>::is_noexcept))
                {
                        return submit(s, r);
                }

        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<const S &, void(const R &)>::overload == call_free,
                typename call_traits<const S &, void(const R &)>::result_type
        >::type

        operator()(const S &s, const R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<const S &, void(const R &)>::is_noexcept))
                {
                        return submit(s, r);
                }

        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<S &, void(const R &)>::overload == adapter,
                typename call_traits<S &, void(const R &)>::result_type
        >::type

        operator()(S &s, const R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<S &, void(const R &)>::is_noexcept))
                {
                        asio::execution::start(
                                (new asio::execution::detail::submit_receiver<
                                        S &, const R &>(s, r))->state_);
                }

        template<typename S, typename R>
        ASIO_CONSTEXPR typename enable_if<
                call_traits<const S &, void(const R &)>::overload == adapter,
                typename call_traits<const S &, void(const R &)>::result_type
        >::type

        operator()(const S &s, const R &r) const

        ASIO_NOEXCEPT_IF((
                call_traits<const S &, void(const R &)>::is_noexcept))
                {
                        asio::execution::start(
                                (new asio::execution::detail::submit_receiver<
                                        const S &, const R &>(s, r))->state_);
                }
#endif // defined(ASIO_HAS_MOVE)
    };

    template<typename T = impl>
    struct static_instance {
        static const T instance;
    };

    template<typename T>
    const T static_instance<T>::instance = {};

} // namespace asio_execution_submit_fn
namespace asio {
    namespace execution {
        namespace {

            static ASIO_CONSTEXPR const asio_execution_submit_fn::impl
            &
            submit = asio_execution_submit_fn::static_instance<>::instance;

        } // namespace

        template<typename S, typename R>
        struct can_submit :
                integral_constant<bool,
                        asio_execution_submit_fn::call_traits<S, void(R)>::overload !=
                        asio_execution_submit_fn::ill_formed> {
        };

#if defined(ASIO_HAS_VARIABLE_TEMPLATES)

        template <typename S, typename R>
        constexpr bool can_submit_v = can_submit<S, R>::value;

#endif // defined(ASIO_HAS_VARIABLE_TEMPLATES)

        template<typename S, typename R>
        struct is_nothrow_submit :
                integral_constant<bool,
                        asio_execution_submit_fn::call_traits<S, void(R)>::is_noexcept> {
        };

#if defined(ASIO_HAS_VARIABLE_TEMPLATES)

        template <typename S, typename R>
        constexpr bool is_nothrow_submit_v
          = is_nothrow_submit<S, R>::value;

#endif // defined(ASIO_HAS_VARIABLE_TEMPLATES)

        template<typename S, typename R>
        struct submit_result {
            typedef typename asio_execution_submit_fn::call_traits<
                    S, void(R)>::result_type type;
        };

        namespace detail {

            template<typename S, typename R>
            void submit_helper(ASIO_MOVE_ARG(S) s, ASIO_MOVE_ARG(R) r) {
                execution::submit(ASIO_MOVE_CAST(S)(s), ASIO_MOVE_CAST(R)(r));
            }

        } // namespace detail
    } // namespace execution
} // namespace asio

#endif // defined(GENERATING_DOCUMENTATION)

#include "asio/detail/pop_options.hpp"

#endif // ASIO_EXECUTION_SUBMIT_HPP
